The Spaniard was subjected to chants of “You don’t know what you’re doing” when he replaced Branislav Ivanovic with Cesar Azpilicueta in the 79th minute and he was also the focus for angry shouts as he walked past the Chelsea supporters at half-time.

Uwe Rosler, the Brentford manager, also appeared to question Chelsea’s work-rate and said that the pressure was now all on the defending FA Cupholders for the replay. When asked about the chants, Benítez argued that his substitutions were vindicated by the two equalising goals.

“I can guarantee that playing Juan Mata, changing the game, we know what we are doing,” he said. “I try to stay really focused. It is a transition period at the club.”

Shaleum Logan, the Brentford left back, believed that the Chelsea players struggled to handle the pressing tactics of his team. “We felt we deserved the win,” he said. “The thing is with world-class players the one thing they don’t like is people in their faces and that’s we did. We got in their faces. We didn’t let them get in a rhythm.”

Benítez was damning in his assessment of Chelsea’s first-half performance but was pleased with their subsequent response and felt that Chelsea should have had a late penalty when Mata’s cross struck Harlee Dean’s arm. “Mata said it was very clear but I’m also very clear,” said Benítez. “We didn’t perform in the first half like we had to.”

Rosler admitted that the “football god” had been in Brentford’s favour but suggested his team had worked harder. “We deserved that luck from what we have put in compared to what Chelsea put in over the 90 minutes,” he said.

“They were surprised by the way that we were set up but we made it difficult. We have no pressure in the replay. The chairman just came to me and said he was delighted. I said: ‘Just make sure that we get something in the playing budget’ and he said: ‘Yes, don’t worry’.

“We have young, British, hungry, well-educated players. It is very important that we try to offer them new contracts to keep them at the club for years.” The replay will be worth around £750,000 to Brentford.

Benítez, by contrast, still seems unhappy with his squad depth. “We are using some players in too many games,” he said. Chelsea are also likely to challenge any extension to Eden Hazard’s three-match ban for appearing to kick a Swanseaballboy when he tried to retrieve the ball during the Capital One Cup semi-final last Wednesday.

The FA has deemed the automatic three-match suspension for his sending off “insufficient”, with Chelsea now preparing their response. “I think that a three-game ban is enough,” said Benítez.